In roll crushers and roll mills, brittle grinding feed is drawn into the roll nip, by means of which the two rotatably supported counter-rotating rolls are separated from each other, and is there subjected to a compressive size reduction. So-called "attrition" size reduction is also known in the roll nip of a high-pressure roll press, in which the individual particles of the grinding feed drawn into the roll nip by means of friction are crushed against one another in the presence of an extremely high pressure in a bed of material, that is, in a pile of material pressed together between the two roll surfaces as achieved by machinery shown in European patent document EP-B 0 084 383. It is obvious that the roll surfaces in such a case are subjected to extraordinarily severe loading and to severe wear.
It is therefore known to make the surfaces of attrition size-reduction roll press wear-resistant by welding a multitude of profiles, such as prefabricated pin-shaped nub pins, to the roll surfaces, which profiles project outward from the roll surface to such a height, and are arranged at such close intervals from one another, that in the operation of the roll press the interstices or pockets between the nub pins remains filled with the compressed fine-grained feed material, which forms an autogenous wear protection for the roll surfaces as shown in FIGS. 4 and 5 of European patent document EP-A 0443 195. The welding on of such prefabricated hub pins is, however, possible only in the case of a pin material that can be surfaced by welding, such as constructional steel or the like. It would also be possible to insert the prefabricated nub pins into respective holes in the roll body and allow them to protrude from the roll body in hedgehog fashion. Such a solution would be expensive from a fabrication standpoint because of the chip-producing boring operations, and presents a risk of cracking, for example in the cylindrical surface of the roll, as a consequence of the high press pressure, which acts via the pin-shaped nub pins on existing notches such as, in particular, at the transition from the roll surface to the lateral, pin surface.